Method of reinforcing box corners and reinforcement therefor



D. E. CLARK May 22, 1 945.

' METHOD OF REINFORCING BOX CORNERS AND REINFORCEMENT THEREFOR Filed Sept. 18, 1943' Patented May 22, 1945 'METHOD OF REINFORCING BOX CORNERS AND REINFORCEMENT THEREFOR Daniel E. Clark, Lynn, Mass., assignor of onehalf to James E. Dakin, Jr., Lynn, Mass.

Application September 18, 1943, Serial No. 502,879

2 Claims.

My present invention is a novel and improved method of reinforcing the corners of boxes, covers, containers, cartons or the like, particularly when made of foldable material; and includes a novel type and construction of reinforcement for use in carrying out my method.

Heretofore it has been customary in making various types of boxes, containers, and, the like,- to cut out from sheet material, such as paper, cardboard, leatherboard, or the like foldable articles, a blank marked, creased, or otherwise formed to fold into the box or coverlike contour. Reinforcing strips of any suitable material, paper,

\ canvas, etc., were applied by adhesive to those parts of the blank sheet material, which were subsequently to constitute the corner portions for the reinforcing of the same, thus giving a double strength at the corners. Furthermore, it is customary to reinforce previously formed box for cover articles by pasting reinforcing layers on the inside or outside of the corner construction.

6 My present method is directed primarily to the folding of flat pre-cut and pre-marked sheet material with thereinforcements positioned at the portions to be subsequently folded into the corners. However, my improved reinforcement may be also applied to previously constructed box covers or cartons, as well as being applied while flat to the blank to be subsequently folded.

I have discovered that the ordinary extra strip pasted on the corners of the flat blank to be formed into a corner when bent or folded into the corner construction is necessarily weakened by the bending action, and the tear-resistance of such an ordinary corner reinforcement is greatly reduced because the reinforcing layer itself is bent and creased with the box material to which it is applied. 6 Y

I have discovered that the corner reinforcement, wherein the reinforcing element is not closely secured to the box element and hence not weakened and creased at the corner construction, results in a greatly increased corner and my present invention and method are directed to incorporate this feature in improving this particular art.

In carrying out my invention; I provide a reinforcement for corner construction which will have a substantially or predetermined portion free of direct attachment with the box element, thus permitting the reinforcing element, or a part of the same, to be free of the creasing, bending, and weakening action to which prior reinforcing strips were subjected.

Thus, in carrying out my invention, I may form strength;

a corner reinforcing member with the foldedover layer, which latter will resist tearing at the corners of the box to which it is secured by retaining its intrinsic strength and, in effect, will stretch or bridge across the sharp cornerusually to which the reinforcing element may be attached.

I may also reinforce such a folded construction by enclosing therein a cord, thread, wire,

tape, or other reinforcing element which will still further strengthen the free part of the reinforcement to stretch or bridge across the corner during use, as well as being free of weakening from the creasing and bending action normally applied to reinforcing layers, thus greatly increasing the tear-resistance and strengthening the entire corner structure.

Referring to the drawing illustrating preferred embodiments of my present invention:

Fig. l is a plan View of a typical foldable box construction shown when fiat with my novel reinforcing elements applied thereto;

Fig. 2 is illustrative of the blank in folded construction with a portion broken away to illustrate my reinforcing corner construction;

Fig. 3 is a perspective view of a typical type of reinforcement for the corners;

Fig.4 is.a modified View also in perspective;

Fig. 5 is a further modification, and

Fig. 6 is a still further modification shown in perspective, and

Fig. '7 is a still further modification shown in fragmentary perspective view.

As shown in Fig. 1, a typical foldable blank from sheet material is indicated wherein the sheet material I has longitudinal cuts 22 and 3-3 at opposite ends to facilitate the folding operation and markings, stamp grooves, or the like 4-4 outlining the bottom contour of the box, and 5--5 for the folded-over end portions when these are used, delineating sides 66, ends l-'!, and foldedover end portions 8-8, with inner sections to be folded 9-9 adjacent each corner. At that portion of the blank I which will constitute the four top corners, I apply by adhesive my novel reinforcing element indicated in Figs. 1 and 2 at I0-l0.

Each reinforcement element l0 may be formed with a flat portion I2 coated with adhesive to be attached to the blank while flat at the points to be subsequently folded into the corner, and at the upper or top part a folded-over section which is free of any adhesive attachment to the box blank and, therefore, will not be deeply creased or weakened during the folding action and will when filled.

As shown in Figs. 1 and 2, this free strip may .comprise a U-shaped portion I5 engaged by a folded-over edge part of the reinforcement l and held in assembled position in any desired way by adhesive, stapling, or the like. Thus when the blank is folded into position with the free ends or tabs 9 on the inside of the fold and the outer end portions 8 doubled over the tabs 8 and over the reinforcing strips, this will leave the portion or layer l free of immediate engagement with the actual corner crease or bend and permit the layer l5 to bridge across the corner, as above explained.

Various modifications of my reinforcement for box corners will readily occur to those skilled in the art. I Also the reinforcements may be made with a double or single fold and, preferably, with a reinforcing cord within the fold, and may be coat ed with adhesive on either face so that the reinforcement is adhesively secured to the box blank with a portion free of such immediate adhesive union to give the bridging effect and freedom from weakening by creasing in the corner during the box-folding operation.

Fig. 3 illustrates a reinforcement strip l6 having its folded-over edge I! enclosing a fiat strip l8. Thus, not only is the edge reinforced by the strip l8 but the folded portion I"! will be free of immediate adhesive attachment to the corner and effect the bridging operation above explained.

In Fig. 4 a somewhat similar construction is illustrated wherein the reinforcing element 20 has an edge 2| folded over a plurality of reinforcing threads or cords 22.

In Fig. 5, the reinforcement folded over a wire or cord 25.

In Fig. 6 a reinforcement 26 is provided with a double U-shaped curved portion 21 and 28, wherein the surface of the reinforcement is coated with adhesive, thus uniting the upper part of 23 has its edge 24 the first fold 28 to the reinforcement 26 and with the adhesive coated surface of the folded portion 21 and the lower part of the reinforcement 26 adapted for contact with the blank, thus leaving the outer fold free for the bridging action above explained.

While I intend that this reinforcing element will be adapted to be applied to the foldable blank while fiat, it will of course be appreciated that my novel reinforcement may also be fitted into a previously formed corner and may be made of any suitable material either paper, canvas, textile material, Cellophane, Koroseal, Vinylite, or the like plastics, which are pliable, thin, strong, and readily handled for this purpose. The strip 18 or the cords 22 may also be of synthetic plastic material, if desired.

The reinforcing elements [0, I6, 20, 23, or 26 may be quickly applied manually, by taping or other applying machines with the adhesively coated surface on the foldable blank in proper position and, thereupon, the folding operation completes the corner reinforcement without further or special operations.

In each case there is a bridging element to reinforce and strengthen the corner, which bridging element is not weakened in strength by the corner-folding action.

I believe that my corner construction, comprising a bridging element is a distinct novelty in this art and I wish to claim the same herein broadly either applied to a flat foldable element before the box-folding operation, or to a completed corner construction.

Also my reinforcing element, while specially designed and serviceable for corner reinforcement, is equally useful and important for a strengthening and reinforcing device on a straight edge, curved portion, as well as at an angle; Furthermore, my reinforcing element is not limited for use with box constructions, but can be advantageously employed in any position and at any joint or place where such reinforcement is desired. While preferably my reinforcing element is adhesively secured to the article, or articles, on which it is desired to use the same, it can be stapled or otherwise attached and thus presents a strong, tear-resistant reinforcement at the strengthened edge. Thus, my improved reinforcing element can be utilized to join two abutting edges or to repair a broken, torn, or injured or partly damaged side section, corner or other part of an article.

I believe that my reinforcing element, having a doubled and strengthened part, layer, strip, cord or cords, fold or the like as herein illustrated, giving in effect bridging or truss-like strength along a predetermined portion, is a distinct novelty in this art, and I wish to claim my reinforcing'element herein broadly.

I claim:

1. A box blank formed and cut for subsequent folding into an open box, container, or the like, said blank while flat having secured on one surface thereof reinforcing elements at the side and end portions to be subsequently folded into corner portions of the box to be made from said blank, each of said reinforcing elements comprising an elongated flat strip having one longitudinal edge only folded over on itself and secured to one side of the element, the unfolded portion only of said side being adhesively coated and secured to the blank.

2. A box blank formed and cut for subsequent folding into an open box, container, or the like, said blank while flat having secured on one surface thereof reinforcing elements at the side and end portions to be subsequently folded into corner portions of the box to be made from said blank, each of said reinforcing elements comprising an elongated flat strip having one longitudinal edge only folded over on itself and secured to one side of the element, the unfolded portion only of said side being adhesively coated and secured to the blank, said element having an additional strengthening element enclosed in said folded portion.

DANIEL E. CLARK. 

